Liquid crystal cells generally used in liquid crystal displays such as a TN liquid crystal cell (TFT), a STN liquid crystal cell (STN) and the like, have a structure in which a liquid crystal component is sandwiched between two glass base materials. On the surface of the glass base material, an optical film such as a polarizing film, phase retardation film and the like is laminated via an adhesive composed mainly of an acrylic resin. An optical laminate composed of a glass base material, adhesive and optical film laminated in this order is in general produced by a method in which first an optical laminated film having an adhesive layer composed of an adhesive laminated on an optical film is obtained, and then, a glass base material is laminated on the surface of the adhesive layer.
Such an optical laminated film tends to generate curl and the like due to large dimension change by expansion and shrinkage under heating or moistening and heating conditions, consequently, there are problems such as occurrence of foaming in an adhesive layer of the resulted optical laminate, generation of peeling between an adhesive layer and a glass base material, and the like. Under heating or moistening and heating conditions, distribution of remaining stress acting on an optical laminated film becomes non-uniform, concentration of stress occurs around peripheral parts of an optical laminate, consequently, there is a problem that light leakage occurs in a TN liquid crystal cell (TFT). For solving such problems, there is a suggestion on an adhesive mainly composed of an acrylic resin having a structural unit derived from N-vinylpyrrolidone which is a kind of monomer having a hetero-cycle in the molecule (Japanese Patent Application Laid-Open (JP-A) No. 5-107410).
However, there is a problem that, when a liquid crystal cell obtained by using an optical laminate having an adhesive layer made of an adhesive mainly composed of an acrylic resin having a structural unit derived from N-vinylpyrrolidone is preserved under moistening and heating conditions, light leakage occurs and durability becomes worse.